The present invention relates in general to flow control devices, and, more particularly, to valves.
In the chemical industry, there is a need for valves which can control the flow of very corrosive fluids, special fluids, and the like, under high vacuum conditions. In all cases, the control of the flow of fluids requires differences in physical size of the valves. There are manufacturing and cost advantages to produce one valve which, with slight modifications, will satisfy all requirements.
There is further need for a valve which can control fluid flow and in which small changes in the valve can produce large variations in fluid flow.
There is also need for a valve which can seal against a surface which varies in dimension and shape.